1. Field of the Invention
The present invention relates to an image signal processor for processing image signals obtained by imaging a subject field with an imaging device, and a method of processing the image signals.
2. Description of the Background Art
Some conventional cameras using silver-halide photosensitive films or digital still cameras have a function, so-called auto-bracketing, that continuously photographs a sequence of frames while gradually shifting the exposure to the underexposure side or overexposure side around the standard exposure of the camera.
A camera using silver-halide photosensitive films which performs auto-bracketing is disclosed in Japanese Patent Laid-Open Publication No. 249534/1993. This camera can decide the parameters, such as the number of frames to be photographed and the exposure correction amount, without receiving instructions from the user.
A camera that performs auto-bracketing according to the prior art photographs a plurality of frames, meaning that the photographed images differ in time. For example, when seven frames are photographed at 0.2-second intervals each at one of seven exposure levels, there is a 1.2-second difference in time between the first frame and the last frame. Therefore, the movement of the object, the change in the photographing conditions, the unintentional movement of the hands of the user in shooting the object, and the like during the shooting period of time make it difficult to appropriately photograph a desired image.